This disclosure is generally in the area of implants which include sensors capable of detecting or interrogating physical, cellular, and other variables, including means for collecting, amplifying, storing and telemetering information as well as a feedback loop and means for modifying the implant after placement in a patient in response to measurements made using the sensors.
Medical implants have been used for many years in interventional radiology, gastroenterology, urology and cardiology and other fields of medicine and surgery. In general, these devices are static and not interactive, i.e., they are implanted for a particular purpose and no change occurs, save for bystander corrosion or biodegradation, over time or for removal in the event a problem develops. Typically conventional implants are fashioned from medical grade stainless steel, compatible polymers, e.g. Dacron(trademark) or Teflon(trademark), or ceramics. More advanced implants have been developed using shape memory metals and polymers. Shape memory is the ability of a material to remember its original shape, either after mechanical deformation, or by cooling and heating. These materials have been proposed for various uses, including vascular implants, medical guidewires, orthodontic wires, etc.
Recently, in an attempt to move implants from being simple structural or augmentative, non-interactive devices, modifications have been made to include a sensor, for example, sensors for cardiac activity or sensors for monitoring blood flow. The sensors measure flow, pressure and/or strain. Most are not remotely xe2x80x9cinterrogatablexe2x80x9d, which is understood to mean that data cannot be extracted remotely, after implantation in a body. Some are remotely interactive, however. For example, particularly with the pacemaker patents, batteries can be re-charged non-invasively. Some sensors are interactive at the site of implantation, but not remotely. Most require some type of xe2x80x9chard-wiringxe2x80x9d to either program the device or to extract data. U.S. Pat. No. 5,411,551 to Winston, et al., describes a stent that includes a sensor located on the inside of the expandable stent wall that is directly connected to a remote monitoring device. U.S. Pat. No. 6,091,980 to Squire, et al., describes a stent including multiple conductive pads to generate a signal when the stent slips or moves from the original position.
An example of a stent which includes a remotely accessible sensor to assist in locating the stent is described in EP 0850654 by Schneider (USA) Inc. U.S. Pat. No. 5,807,259 to Cimochowski, et al., U.S. Pat. No. 6,053,873 to Govari, et al., and U.S. Pat. No. 6,015,387 to Schwartz, et al. describe a device which is implantable to monitor flow and/or pressure in a vessel, graft or prosthetic. The ""259 and ""873 pressure sensors include a radio coil for remote access of the data which is transmitted as ultrasonic waves by a transducer. The ""387 sensor generates an electromagnetic, ultrasonic and/or radio frequency signal indicative of the rate of blood flow in the associated vessel. U.S. Pat. No. 5,833,603 to Kovacs, et al. describes an implantable transponder including a sensor for temperature, strain, pressure, magnetism, acceleration, ionizing radiation, acoustic waves, or chemicals, where the sensor can be associated with an implanted prosthetic or graft. Data is transmitted to a remote reader. U.S. Pat. No. 5,709,225 to Budgifvars, et al., assigned to Pacesetter AB, describes a medical implant containing a magnetic field detector with a capacitative sensor detecting changes in the presence of a magnetic field, and means for generating a remotely-detectable signal, for use in determining an appropriate medical therapy. U.S. Pat. No. 5,928,248 to Acker describes a stent including a system which transmits non-ionizing fields between a transducer or transducers on the probe and external transducers, to aid in positioning of the stent.
None of these devices, however, are responsive to the data which is collected by the sensors. None of these devices incorporates means of repeated or interval or programmed interrogation, via either intrinsic or extrinsic interrogative means. None of these devices incorporates within the device means for signal processing and interpretation. None of these devices includes means for raw or processed data storage. None of these devices has incorporated intrinsic or proximate means for change, i.e. alteration of the local environment or local or distant therapy as a result of gathered information. Further, none of these devices has the ability to telemeter and interact with data transmission or communication means which exist as single or mutiple e.g. nested, loops of information transfer. Therefore it is an object of the present invention to provide a method, devices, and systems incorporating such devices, for implantation in a patient wherein the implant includes means for collection, and/or processing and/or storage of data.
It is another object of the present invention to provide a method, devices, and systems incorporating such devices, for implantation in a patient wherein the implanted device includes means for telemetry or communication of data for subsequent interaction with data transmission or communication means, in single or mutiple such as xe2x80x9cnestedxe2x80x9d, loops of information transfer.
It is another object of the present invention to provide a method, devices, and systems incorporating such devices, for implantation in a patient wherein the implant includes means for responding, such as mounting of a therapeutic action, on the basis of either local data collected or external dependent or independent signals.
Implantable devices (i.e., xe2x80x9cimplantsxe2x80x9d), including sensors for data measurement, and/or data analyzers, and/or data storage means, and/or data telemetry/transmission means including means for communication at mutiple levels of isolated or nested levels of information transfer have been developed. These devices may have incorporated means for modification of the implant or mounting a response, e.g. local or systemic drug delivery, in response to measurements made using the sensors. These are particularly useful in urology, hepatology or cardiology, where the implants contain one or more sensors responsive to variables which change over time, for example, pressure which is indicative of changes in fluid flow and diameter of the ureter, biliary duct or vessel in which the implant has been placed. Feedback from the sensor(s) either directly, or indirectly via monitoring means external to the patient, signal changes that may be required, such as expansion of the implant in the case where the tissue lumen diameter changes over time or the implant becomes unstable or migrates. In another embodiment, the implant contains a bioactive, prophylactic, diagnostic or pH modifying agent. In one embodiment, the implant is formed of a temperature or pH responsive material so that the agent is released when the temperature or pH is altered.
These systems can also be used to connect a patient to a remote data storage or manipulation system, such as a watch-like device, small portable device, intra or extradermal implant, phone system devices (portable phones, answering services, beepers, office fax machines), portable computer, personal digital assistant (PDA, e.g., Palm Pilot(trademark) systems), or to the internet (world wide web) or a computer accessible through devices that the physician or nurse can monitor or use to interact remotely with the implant.